/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package hivemall.utils.hashing;

import hivemall.utils.math.MathUtils;

public abstract class HashFunction {

    public int hash(Object data) {
        String s = data.toString();
        return hash(s);
    }

    public static int hash(final int first, final int second, final boolean positive) {
        final int h = first * 157 + second;
        if (positive) {
            int r = MathUtils.moduloPowerOfTwo(h, MurmurHash3.DEFAULT_NUM_FEATURES);
            if (r < 0) {
                r += MurmurHash3.DEFAULT_NUM_FEATURES;
            }
            return r;
        }
        return h;
    }

    public abstract int hash(String data);

}
